1. Field of the Invention
This invention generally relates to a sorting apparatus for image forming apparatus, and more particularly, to a sorting apparatus which is electrically operable independently from the image forming apparatus.
2. Descriptions of Prior Art
In this specification, it is defined that the terminology "image forming apparatus" is understood as not only the normal copying machines, but also facsimiles, laser printers, duplicating machines and so on. It is therefore defined that the word "copy" is understood as "a paper sheet on which an image of an original document is formed".
Generally speaking, the sorting apparatus as mentioned in the preamble must recognize user's operation conditions for the image forming apparatus, such as the copy quantity, and the substitution of documents. For instance, to recognize the document substitution, the sorting apparatus is usually clasified into two types i.e., one for requiring the transmitter/receiver which may communicate the signals to the sorting apparatus, and the other for no requirement of the transmitter/receiver.
In the former sorting apparatus, such a transmitter/receiver is unnecessary when the user wishes to operate the image forming apparatus without using the sorting apparatus. Moreover there are disadvantages that the entire construction of the sorting apparatus is complicated, and the inter connection between the sorting apparatus and the image forming apparatus gives inconvenience to the user.
On the other hand, the latter sorting apparatus usually comprises detection means which may detect image-recorded materials (=copy paper or sheets) delivered in turn from the copying machine in order to recognize the document substitution.
Various recognition means have been proposed.
For example, one recognition mean is provided in the sorting apparatus that delivery time intervals "TI" of a plurality of copies which are in turn delivered from the copying machine are detected so as to recognize the document substitution. If the detected delivery time interval "TI" exceeds a predetermined time "Ts", the sorting apparatus may recognize that the document substitution is most probably done by the user, so that it may set the sorting condition for the new document.
In the sorting apparatus of te type, so-called "an auto-reset mechanism" is provided to return the copy holding bins to the non-sorting mode when the first sorting operation is completed so as to perform correctly a second sorting operation.
An explanation of this auto-reset mechanism will be briefly made as follows. That is, the quantity setting of the sorting operation by one user in this sorting apparatus may be determined by a plurality of copy sheets with respect to the first original document in case of the sorting mode. Accordingly the same user must set again the sorting mode if the sorting quantity for the second original document is different from the first one. If another user however wishes to sort the copies based upon newly-set quantity of the copy, the sorting operation is mistakenly effected because the previously-set sorting quantities are being stored in the memory. The function of the auto-reset mechanism is therefore to return the non-sorting mode (=normal single copy mode) when the sorting apparatus is not continuously operated for more than a predetermined time period so as to avoid such troubles.
However, the following disadvantages are provided in the auto-reset mechanism. That is, when the above-described auto-reset operation begins, the sorting bins are transported to the non-sorting bin position. Since this bin transportation is effected by mechanical means, the total time of the bin transportation requires considerably longer than the copy duplicating time (the copying speed). As a result if the copying machine is mistakenly operated during the bin transportation, the mulfunction, e.g., a paper jam occurs because as previously described, the copying machine is not electrically communicated to the sorting machine. Furthermore when the paper supply cassette becomes empty during the copying operation, the auto-reset mechanism may be occasionally in operative during a replenishment of the copy paper into the paper supply cassette. Consequently if the user doesnot become aware of the operation of the auto-reset mechanism and continues the copying operation, all of the copy paper is held in a single sorting bin under the non-sorting mode.
A primary object of the invention is to provide a sorting apparatus for an image forming apparatus in which the succeeding sorting operation is automatically performed by erasing the memory content (copy quantity) of the preceding sorting operation when the delivery of a copy is not detected for more than a predetermined time period.
A secondary object of the invention is to provide a sorting apparatus for an image forming apparatus, which sorting apparatus is not electrically communicated to the image forming apparatus.